Container closure with vent opening means

ABSTRACT

A container wall or end closure is provided which has a hollow upwardly convex embossment formed in it, and at least one radially extending score line in an outer portion of the embossment which will be ruptured to form a vent opening in the closure when force is applied against the center of the embossment. The container wall may further include an inclined wall formed therein around the periphery of the embossment and a thinned zone or band of material in such wall to facilitate rupture of the score in the embossment. A method of forming such a container closure is also provided.

United States Patent Clawson et al.

[73] Assignee: Aluminum Company of America, Pittsburgh, Pa.

[22] Filed: Aug. 18, 1972 [21] Appl. No.: 281,715

[52] US. Cl. 215/307, 215/253 [51] Int. Cl 1.B65d 51/16 [58] Field of Search 220/48, 27, 89 A; 229/7;

[56] References Cited UNITED STATES PATENTS Towle 222/541 X Coffman 220/89 A 1 Dec.3,1974

3,003,668 10/1961 Sherlock ct al 222/541 3,410,436 11/1968 Foss et al H 215/56 Primary ExaminerGeorge T. Hall Attorney, Agent, or Firm-David W. Brownlee [57] ABSTRACT A container wall or end closure is provided which has a hollow upwardly convex embossment formed in it, and at least one radially extending score line in an outer portion of the embossment which will be ruptured to form a vent opening in the closure when force is applied against the center of the embossment. The container wall may further include an inclined wall formed therein around the periphery of the embossment and a thinned zone or band of material in such wall to facilitate rupture of the score in the embossment. A method of forming such a container closure is also provided.

6 Claims, 6 Drawing Figures BACKGROUND OF THE INVENTION It is known to provide means in a container closure for releasing a vacuum or pressure in a container on which the closure is secured in order to facilitate removal of the closure from the container as is disclosed in US. Pat. Nos. 1,718,459 and 3,446,383. According to those patents, a tool such as a fork may be inserted in an opening in the closure to break a seal between a gasket in the closure and the bottle finish to permit venting of the bottle.

It is also known, as is disclosed in US. Pat. No.

. 1,743,283, to provide a rosette or other similar figure in the material of a can top to weaken the top and assist the consumer in forming a vent opening in the can top. It is further known, as is disclosed in US. Pat. No. 1,296,341, to provide a container wall with a boss init and a groove around the boss having a weakened line in its bottom to be ruptured to form a vent opening in the container wall. There are also several patents including US. Pat. Nos. 3,246,791, 3,362,569 and 3,410,436, among others, which disclose container closures with embossed buttons formed therein and score lines around the buttons which may be ruptured by depressing the buttons with ones'fmgers or other pressure applying means. See also US. Pat. No. 3,262,6l I.

It is desirable to provide a container wall such as a closure or can end which includes means for forming a vent opening with a minimum of effort and without the need for a tool such as a fork or the'like.

SUMMARY OF THE INVENTION This invention provides a container closure with a hollow embossment formed in it which slopes outwardly from its center of its base, and further has, at least, one radially extending weakening line cut part way through the material ofthe container closure in the outer portion ofthe embossment. An inclined wall which includes a zone of reducedmaterial thickness may connect the base of the embossment with the sheet material of the closure therearound for facilitating rupture of the score or scores in the embossment. This invention also provides a method of forming such a vent opening means in a container wall.

Accordingly, an object of the invention is to provide a container closure having means therein for forming a vent opening.

I Another object of the invention is to provide a container closure having an embossment formed therein and at least one radially extending weakening line in the embossment which can be ruptured by depressing the embossment.

A further object of the invention is to provide a vent opening means in a closure which leaves visible evidence when the closure has been opened or tampered.

Another object of the invention is to provide a method of forming a vent opening means in a container closure.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects and advantages of the invention will be more fully understood and appreciated with reference to the following description and the drawings appended hereto wherein:

FIG. 1 is a top plan view of a container closure of the invention,

FIG. 2 is a partial cross-sectional view of the container closure of FIG. 1 secured on a container,

FIG. 3 is an enlarged partial cross-sectional view illustrating manipulation of the vent opening means in the closure of FIGS. 1 and 2 to rupture the scores in the closure,

FIG. 4 is an enlarged top plan view of the vent opening means of FIG. 3 showing the forces in the closure during opening,

FIG. 5 is a cross-sectional view of tools which may be used to form an embossment in a container closure in accordance with the invention, and

FIG. 6 is a partial cross-sectional view of an alternative embodiment of a closure of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS AND A METHOD OF FORMING THE SAME Referring to FIGS. 1 and 2, a preferred embodiment of the invention is illustrated as comprising a metal closure 10, preferably made of aluminum or an alloy thereof, having a top end wall or panel 12 and a depending peripheral skirt 14 with a bead 16 on its bottom edge, and further including a vent opening means formed in the top end wall. Closure 10 is adapted to be held in a sealed condition on a container mouth by a vacuum in the container, so the closure includes no threads, lugs or other mechanical means for securing it on a container. Such a vacuum sealed container closure assembly can be opened by venting air into the container to relieve the vacuum therein which releases the closure from the container.

According to this invention, a vent opening means in such closure may comprise an upwardly domed embossment 18, an inclined wall 20 extending upwardly and outwardly from the base of the embossment 18 to the end wall 12 therearound, and four radially extending score lines.22 in the outer portion of the embossment. Although the length of score lines 22 is not considered to be critical, they preferably extend at least into wall 20. Such scores may be out either in the inside or outside surface of closure 10. Embossment l8 and inclined wall 20 combine to form an upwardly open groove in top end wall 12 of closure 10. Wall 20 may have a thinned portion 24 formed therein to weaken it and thereby facilitate rupture of scores 22 as will be explained.

In the embodiment selected for illustration, which is particularly adapted to have an opening formed therein to vent a container on which the closure is applied, embossment 18 is symmetrical about a vertical line through the center of the embossment and has an up- .wardly domed, arcuate cross-sectional configuration. It

the embossment upwardly to rupture the score. An embossment in an end closure of the invention may also have an elliptical, oval or conical shape, although a substantially hemispherical-shaped embossment is preferred. Further, a closure of the invention is not limited to four scores as in closure 10 which is illustrated in FIGS. 1 and 2.

As seen in FIG. 2, top end wall 12 of closure 10 includes a recessed central portion with a raised channel *therearound comprising an inclined wall portion 25, a

horizontal wall portion 26 and a beaded corner 27. Gasket material 28 such as foamed polyvinyl chloride may be disposed against the undersurface of the raised channel for sealing closure 10 against a container mouth. Although it is not critical to the invention, it is desirable for the top of embossment 18 to lie in approximately the same plane or below the recessed central portion of closure 10 to protect the embossment from being accidentally depressed when containers are stacked on top of one another or when a price stamp is applied to such a closure. If embossment 18 were accidentally depressed, one or more of score lines 22 could be ruptured to vent a container on which closure 10 is sealed, and such venting of the container could result in spoilage of the contents of the container and- /or separation of the closure from the container.

FIG. 2 further illustrates an exemplary container 30 on which closure 10 may be sealed. Container 30 has a mouth configuration which includes an upwardly facing top sealing surface 32 and a side surface 34 with a plurality of outwardly projecting beads 36 thereon extending around the bottle mouth. In one embodiment of such container 30, four such outwardly projecting circumferentially spaced beads 36 may be provided on side surface 34 and each such bead may include an arc length of degrees to 60.degrees around the circumference of the bottle mouth. The number and arc length of these beads may vary with the diameter of the closure and container. Such beads 36 preferably have a frictional interference with closure skirt '14 to provide a limited amount of resistance against removal of closure from the container 30 after the vacuum in the container has been relieved. Such frictional interference makes closure 10 more suitable for use as a reclosure after initial opening of container 30. A plurality of spaced beads 36 are preferably provided on the container finish, rather than one continuous bead, because the spaced beads permit a closure to be deformed slightly by going out-of-round over and between such beads to facilitate application of a closure on the container, and to accommodate glass tolerances. If a container had one continuous bead around its mouth, it might be difficult or impossible to position a closure on the container when the interference between the beads and the closure skirt 14 is on the high side due to variations in the tolerances permitted informing such container and closure. Such a continuous bead would not permit the closure to deform to fit thereover.

FIGS. 3 and 4 illustrate opening a venting means in a container closure 10 of the invention. This may be done by applying pressure against the top of embossment 18 by means of the thumb, finger or the like to depress the embossrnent to approximately the shape and position shown by the ghost lines in FIG. 3. Depressing embossment 18 tends to flatten the embossment which spreads the peripheral portion or base of the embossment as indicated by the arrows in FIGS. 3 and 4. This increases the circumference of the embossment and stretches the metal in the base of the embossment, or produces tensional stresses therein, and ruptures scores 22 in such periphery as is illustrated in FIG. 4. The shape of ruptured scores 22 is exaggerated slightly in this figure for purposes of illustration. In an actual closure, the change in the appearance of the scores due to rupturing may be almost imperceptible to the naked eye. For purposes of the invention, the size of the opening which is produced by the ruptured scores is not considered to be critical because even a small opening will effectively vent air into a container to permit relatively easy removal of the closure from the container.

In some embodiments of this invention, embossment 18 may be deformed to have a downwardly convex configuration when it is depressed to rupture score lines 22 therein. Such reversal of embossment 18 is readily apparent to a consumer and therefore provides visual evidence that a package with closure 10 thereon has been opened or tampered.

In opening a vent means of the invention, it is believed that inclined wall 20 and thinned zone 24 in such wall facilitate rupture of scores 22 because the wall and thinned zone reduce the restraint against flattening of the embossment. If no such inclined wallwere provided, the metal in closure 10 around embossment 18 would provide more resistance against depressing and flattening the embossment because such metal could not accommodate an increased diameter of the embossment except through buckling or wrinkling of the metal which would require substantial force. When embossment 18 is depressed in a closure which includes an inclined wall 18, the wall can easily pivot or hinge outwardly, especially when it has a thinned zone 24 therein which weakens the wall to permit bending along the zone. Preferably, thinned zone 24 is located relatively high in wall 20, or close to the material in closure 10 adjacent the wall, to further facilitate outwardly pivoting of the lower portion of the wall.

Once a closure of the invention has been vented by depressing embossment 18 to rupture scores 22, the closure can be easily removed from container 30 by simply lifting it off the container. As explained above, a frictional interference fit of a few thousandths of an inch may be provided between the skirt of the closure on container beads 36 so the closure will not be accidentally dislodged from a container, but can be removed from a container with ease. After initial venting of closure 10 for removal of the closure from a container, the closure can be used to reclose the container for temporary storage. Such vented closure is not intended for use in hermetically resealing a container since the closure has the vent opening in its top end wall.

FIG. 5 illustrates exemplary tools which may be used to form an embossment in a sheet of material such as a metal container closure in accordance with this invention. Preferably, the top panel will have been scored prior to having the embossment formed therein. The closure can be formed before or after the opening device has been formed. The exemplary tools include an upper forming ring 50 with a rounded working end or nose '51, an upper holddown member 52 around the ring, a lower annular forming member 54 with an upwardly and inwardly facing angular forming surface 56 on its top inner corner, and a center punch 58 with an upwardly arcuate working surface 60 over which an embossment can be formed.

In the operation of such tools, a sheet of material such as a metal container closure 62, which is preferably made from aluminum alloy sheet material, is placed between annular member 54 and holddown member 52 which is clamped against the closure, and ring 50 is moved downward against the closure to draw metal from the closure into the groove formed by the two lower dies. Rounded nose 51 on ring 50 then coins the metal in closure 62 against angular surface 56 on annular member 54, which extrudes metal inwardly and downwardly into the groove between the punch 58 and annular member 54. This further forms the metal from closure 62 over punch 58 to produce an upwardly convex embossment 64 with a groove 66 around the embossment. As formed, the outer wall of groove 66 has a narrow band or zone 68 in which the metal of the closure is thinner than is the original thickness of the metal. As explained above, such thinner band or zone of material '68 in the wall of the groove increases the flexibility of the wall to facilitate rupture of scores in the sheet.

FIG. 6 illustrates an alternative embodiment of the invention which comprises a metal sealing disc 70 having a vent opening means in its center, and a plastic cover cap 72 over the disc. Disc 70 is adapted to be held in a sealed condition on container 82 by a vacuum in the container and therefore does not include mechanical means for securing it on the container. A vacuum sealed package with disc 70 thereon can be opened by venting air into the package to relieve the vacuum and release the disc from the container. In accordance with this invention, a vent opening means in disc 70 may include an upwardly convex embossment 74 in the disc, at least, one radially extending score line (not shown) in the periphery of the embossment, and an annular wall 76 inclined upwardly and outwardly from the base of the embossment to the sheet metal therearound. Annular wall 76 may have a thinned annular zone 78 in it to facilitate rupture of the scores in the disc as was explained with respect to the embossment illustrated in FIGS. 1-4. Disc 70 may also have a ring 80 of gasket material on its undersurface for seating against the top of container mouth 82.

Plastic cover cap 72 includes a top end wall 84 with an annular rib 86 on its undersurface for disposition in the groove in disc 70 formed by embossment 74 and annular wall 76, and a depending peripheral skirt 88. Such skirt may have an inwardly projecting circumferential edge flange 90 thereon for engagement under container bead 92 to retain the cap on the container, and an outwardly projecting circumferential edge flange 94 for facilitating removal of the cover cap from container mouth 82 with ones thumb or fingers. Annular rib 86 on cover cap 72 is provided to help prevent accidental rupture of the scores in disc 70. With a cover cap 72 having such rib 86, force applied against the top of the cover cap will be supported by substantially the entire surface of disc 70 so that embossment 74 will not be thereby depressed within the disc to rupture the scores in the embossment. In order to depress embossment 74 with disc 70 and thereby rupture the scores in the embossment, cover cap 72 must first be removed. Rupture of the scores in disc 70, vents ambient air into container 82 so that the disc is no longer held against such container and can be easily removed,

After opening, cover cap 72 is available for use to reclose container 82.

From the above description and the drawings appended hereto, it is seen that this invention provides a container wall such as a closure or can end having a venting means therein which may be opened by pressing with the thumb or finger, and a method of forming such a venting means. Although a preferred embodiment of such a closure and a preferred method of forming the same have been illustrated and described, it will be apparent to those skilled in the art that numerous variations can be made in the closure and the method without departing from the scope of the appended claims. For example, a closure of the invention may have threads rolled in its skirt to secure it on a threaded container, and may have a pilferproof locking band on the bottom edge of the skirt. The venting means of the invention may also be formed in a can end for venting a can on which the end is sealed to facilitate opening of the end without spraying of the contents of the container on the user. As explained above, the venting means of the invention may also be formed in a safety closure in which the score lines in the venting means will automatically rupture when excessive pressures are present in a container on which the closure is sealed. Further, the score lines or weakening lines in a closure of the invention may be formed by any of a variety of known methods.

What is claimed is:

l. A metal container wall which includes a vent opening means comprising a hollow flexible embossment of generally hemispherical shape formed integrally in said container wall, an integral annular wall around said cmbossment extending at an angle from the outer periphery thereof to said container wall around the embossment to permit radial expansion of the embossment in response to pressure applied thereagainst, and further having at least one radially extending weakening line in the outer periphery of the embossment which is adapted to be ruptured upon radial expansion of the embossment.

2. A container wall as set forth in claim 1 in which said annular wall has a thinned zone therein.

3. A container wall as set forth in claim 1 in which said embossment is upwardly convex.

4. A container wall as set forth in claim 3 in which an inclined wall extends upwardly and outwardly from the base of said embossment to the container wall therearound.

5. A container wall as set forth in claim 4 in which the top of said embossment is at or below the top surface of the container wall therearound.

6. A vacuum sealed container-closure assembly comprising a container with a mouth opening including a top sealing surface and an outer side surface, and a metal closure on the container having a top end wall with gasket material on its undersurface around the periphery thereof for sealing against said top sealing surface of the container and a vent opening means in said top end wall including an upwardly convex flexible embossment, an integral annular wall around said embossment extending at an angle from the outer periphery thereof to said top end wall around the embossment to permit radial expansion of the embossment in response to pressure applied thereagainst, and at least one radially extending score line in the outer periphery of the embossment which is adapted to be ruptured upon radial expansion of the embossment. l 

1. A metal container wall which includes a vent opening means comprising a hollow flexible embossment of generally hemispherical shape formed integrally in said container wall, an integral annular wall around said embossment extending at an angle from the outer periphery thereof to said container wall around the embossment to permit radial expansion of the embossment in response to pressure applied thereagainst, and further having at least one radially extending weakening line in the outer periphery of the embossment which is adapted to be ruptured upon radial expansion of the embossment.
 2. A container wall as set forth in claim 1 in which said annular wall has a thinned zone therein.
 3. A container wall as set forth in claim 1 in which said embossment is upwardly convex.
 4. A container wall as set forth in claim 3 in which an iNclined wall extends upwardly and outwardly from the base of said embossment to the container wall therearound.
 5. A container wall as set forth in claim 4 in which the top of said embossment is at or below the top surface of the container wall therearound.
 6. A vacuum sealed container-closure assembly comprising a container with a mouth opening including a top sealing surface and an outer side surface, and a metal closure on the container having a top end wall with gasket material on its undersurface around the periphery thereof for sealing against said top sealing surface of the container and a vent opening means in said top end wall including an upwardly convex flexible embossment, an integral annular wall around said embossment extending at an angle from the outer periphery thereof to said top end wall around the embossment to permit radial expansion of the embossment in response to pressure applied thereagainst, and at least one radially extending score line in the outer periphery of the embossment which is adapted to be ruptured upon radial expansion of the embossment. 